不同过渡电阻下小电流接地故障暂态选线的适用性分析

Adaptability Analysis of Transient Line Selection of Small Current Grounding Fault under Different Transition Resistances

暂态原理选线方法是近年来小电流接地故障检测技术的一个重要进展,其中故障点过渡电阻对故障暂态过程和选线方法适用性有决定性的影响。针对低阻和高阻接地情况,分析总结了不接地系统和经消弧线圈接地系统中故障暂态的谐振机理、暂态形态特征、暂态分布特征以及过渡电阻对暂态电流幅值、相位、衰减因子的影响,并分析了现有暂态选线技术的适用性。结果表明:对于小电流接地系统低阻欠阻尼接地故障,现有暂态选线方法是适用的;对于不接地系统高阻过阻尼接地故障,现有暂态选线方法仍适用,但需要提高信号传输与选线装置采集精度;对于谐振接地系统高阻欠阻尼接地故障,现有暂态选线方法不能适用,需要研究新的选线算法。

The transient line selection method is one of the important developments of small current grounding fault detection technology in recent years,in which the transition resistance of the fault point have a decisive influence on the feasibility of the fault transient process and line selection method.Aiming at low resistance and high resistance grounding situations,the transient resonance mechanism of fault,the transient morphological characteristics,the transient distribution characteristics and the influence of transition resistance on the amplitude,phase and attenuation factor of transient current in both non-grounding system and arc extinction coil grounding system are analyzed and summarized.The adaptability of existing transient line selection technologies is also analyzed.Results show that:the existing transient line selection method is adaptable to low resistance and under damped grounding faults in small current grounding system;the existing transient line selection method is still adaptable to high resistance and over damped grounding faults in non-grounding system but the signal transmission and the acquisition accuracy of line selection equipment should be improved;the existing transient line selection method is not adaptable to high resistance and over damped grounding faults in resonance grounding system and new line selection algorithm should be studied.